Proceedings of' the Royal Society of Edinburgh. 191 



which is confounded with the common carboniferous or mountain 

 limestone of marine origin, is, in his opinion, of fresh-water origin. 



On an irregular line extending from Joppa on the coast of the 

 Firth of Forth, in a south and south-west direction to the Pentland 

 Hills, strata of mountain or carboniferous limestone crop out at in-» 

 tervals ; and their marine origin is indicated by encrinites, the Pron 

 ductus, &c., and corallines. This limestone is developed with the 

 least interruption between Edmonstone and Muirhouse, where it is 

 from twelve to twenty feet thick or more. Along this part of the 

 line may be seen fractures and elevations of the strata of limestone 

 and superincumbent shale and sandstone, evidently occasioned by a 

 sudden and violent uplifting force acting from north-east to south- 

 west, and causing the strata which were the subject of this convulsion 

 to dip south-east at an angle of 25°. These uplifted beds, between 

 Edmonstone and Muirhouse, and subsequently to Burdiehouse, form 

 the strata which dip under the coal-measures of Gilmerton, Loan- 

 head, and other sites. 



At IMuirhead Quarry the same mountain limestone is seen, but a 

 covered state of the ground succeeds in the same south-west direction 

 for a mile, in which no outcropping strata are observable, except some 

 beds of sandstone about the middle of that space, dipping with the 

 other strata towards the south-east at an angle of 25**, and placed 

 higher than the limestone. 



At the south-west termination of this space is situated the Quarry 

 of Burdiehouse. It is difficult to determine, from the covered state 

 of the ground, whether the bed of limestone here seen is lower or 

 higher than the mountain limestone hitherto described ; possibly the 

 mountain limestone may here thin oflP, and be replaced by the Burdie- 

 house bed. The appearance of the strata, however, which crop out 

 between Burdiehouse and Loanhead, dipping near the former site 

 towards the south-east at an angle of 3C, and towards the latter at 

 a less angle in the same direction, shew that the limestone of Bur- 

 diehouse, in common with the mountain limestone cropping out be- 

 tween Edmonstone and Muirhead, is lower, and therefore of older 

 formation than the coal-measures of Gilmerton and Loanhead. Hence 

 the limestone of Burdiehouse and the mountain limestone of marine 

 origin, are jointly referable to one common epoch of formation. 



The Burdiehouse limestone, however, is clearly not of marine, but 

 of fresh-water origin. It forms a bed of twenty-seven feet in thick- 

 ness, composed of strata about four and a-half feet thick, dipping 

 south-east at angles of 23° and 25°, with the seams of stratification 

 regular and continuous, and also with intersecting vertical seams. 



